Oil separator in refrigeration systems



April 15, 1947; J. R. ZWICKL 2,413,962

OIL SEPARA TOR IN A REFRIGERATION SYSTEM I Filed June 6, 1945 ATTORNEYPatented Apr. 15, 1947 Joseph a. Zwickl, East Orange, N. 1., assignor toV Worthington Pump and Machinery Corporation, Harrison, N. 1., acorporation of Delaware Application June 6, 1945, No. 597,742

' a 7 Claims.

This invention relates to refrigerating syst .of the closed circuit typeutilizing a compressor, condenser, and evaporator or cooler, and inwhich system a refrigerant such as those of the well known Freon typesis compressed, condensed, and evaporated to provide the refrigeration orcooling of the medium to be cooled.

- In such systems,.lubricating oil lost by the compressor is picked upby the refrigerant liquid, and accumulation of such oil in therefrigerating fluid impairs the efliciency of the heat transfer in theevaporator or cooler, resulting in a lowering of the eiliciency of thesystem. a

It is an object of the present invention to provide means for removingor separating such oil out of the refrigerant fluid and returning theoil to the compressor or compressors for re-use as a lubricant. V a

In such systems employing a number of compressors, each compressor losesa difierent amount of oil, and, consequently, the demands for returnedoil of the different compressors vary; therefore, it is another objectofthe present invention to provide means whereby the quantity of there-claimed or released oil delivered to the respective compressors iscontrolled by the quantity of oil in the compressor which is availablefor lubricating purposes.

With these and other objects in view, as may appear from theaccompanying drawing, the invention consists of various features ofeonstruction and combination of parts, which will be first described inconnection with the accompanying drawing showing a refrigerating systemof the preferred form in diagram with parts in section and partly indiagrammatic elevation, and the features forming the invention will bespecifi-' cally pointed out in the claims.

Referring more particularly to the drawing, the improved refrigeratingsystem includes an evaporator l of any approved type in which therefrigerant is evaporated to provide refrigeration for cooling themedium to be cooled which, as is usual in refrigerating systems,'jiscirculated I through the evaporator. 'The vaporous refrigerant passesfrom theevaporator to the compressor or compressors. In the drawing, two

. such compressors 2 and 3 are shown, but it is to be understood thatany number of compressors may be employed withoutvdeparting, from the,

spirit of the present invention and that these compressors may be of thereciprocating type as shown, or of a well known centrifugal type. Thevaporized refrigerant which flows from the evaporator I through the line4 into the suctions 5' of the compressors is compressed and returns fromthe discharges 6 of the compressors through a suitable line 1 to thecondenser 8.

During the operation of the apparatus, oil is lost by the compressorsand finds its'way through the system into the liquid "refrigerant in theevaporator I. Such oil must be; removed so as to prevent any excessiveoil accumulation within the sysetem which would impair the efliciency ofthe heat transfer in the evaporator or cooler, and it is desirable toreturn such oil to the compressor or compressors.

The oil and non-evaporated refrigerant in the evaporator or cooler Ifallsto the lowest part of .the evaporator and into a well orcompartment indicated at 9, although the well or compartment 9 may beeliminated if desired, and the contaminated liquid refrigerant may beallowed to collect in the lowermost portion of the evaporator or cooleri1 Y From the deepest point of the evaporator or cooler i, which in thedrawing is shown as the well 9, a small stream of the liquid, that is,the refrigerant and oil, is drained through a suitable pipe or conduitill in which is 10 ted a solenoid operated valve II and a needle alvel2. The liquid withdrawn from the even ator I through the pipe I0 isdelivered into tlif annular upper chamber iii of the oil separatogfstructure M. A pipe coil I 5 is located in the upper annular chamber l3,and it has connection through a suitable pipe IS with the discharge pipe1 from the compressors 7! and 3 to the condenser 8 for receiving hotdischarge gas from the point in the system where the temperature of thegas is highest. The sensible and latent heat of the high pressure'gasdelivered to the coil I5 is given off as the gas condenses in the coill5 during the heating of the liquid delivered to the annular chamber I 3through the pipe Ill. The condensate from the lowermost part of the coil[5 is returned through a suitable pipe connection I! either to the maincooler or evaporator i, or to any other suitable point in the systemwhereinthe pressure is less than the pressure in the condenser 8.

The liquid refrigerant whichlis contaminated with oillenters the annularchamber I 3 at the l3 into the main suction line l from the evaporatorto the compressors. As more and more of the refrigerant is vaporized andreturned as a gas or vapor to the main suction line 4, the oilconcentration in the residue of liquid rises steadily and itstemperature increases. As the oil rises in the annular chamber |3, itreaches the overflow opening l9 through which it flows over the weir 20into the oil storage compartment 2|. A temperature bulb 22 extends intothe oil separator l4 and it is positioned so that the oil flowingthrough the opening l9 and over the weir 20 must contact the temperaturebulb.

The temperature bulb 22 is of the usual type of thermostat bulb whichwhen subjectedto a predetermined temperature degree will operate thethermostat 23 of any approved construction to close the electricalcircuit of the solenoid 24 of the solenoid valve l|, opening the valveand allowing the liquid to flow from the evaporator l into the annularchamber l3. The rate of flow of the liquid into the annular chamber I3is regulated by means of the needle valve l2. At such time that thetemperature oi liquid in contact with the bulb 22, is below apredetermined derequired by it, the solenoid valves 29 are pro-- vided.The solenoids 33 of these valves 28 are connected in the electricalcircuit with the floatactuated switches 3|.

When the oil level in any one of the compressors falls to apredetermined level, that is, to a point where the compressor needs anadditional supply of oil, its switch 3| will be closed which will causeenergization of the motor 32 and the starting of the pump 28. At thesame time, the solenoid 33 of the valve 29, which is in the supply line28 to the compressor needing oil, will be energized which will open thevalve and. allow oil to flow into that compressor until such time as thelevel of oil in the compressor reaches a height to open the switch 3|and break the electrical circuit through the motor 32 and the solenoid33. If the other compressor in the systemdoes not need oil at the sametime as the closing of the electrical circuit of the motor 32 by anotherof the compressors, its solenoid-actuated valve will remain closed whichwill prevent the delivery of oil to gree, due to the presence of toomuch liquid refrigerant in the mixture the thermostat 23 operates toclose the solenoid-actuated valve II.

If the flow of the liquid refrigerant, contami-,

nated with oil, to the chamber I3 is too fast, insuflicient refrigerantwill be vaporized in the chamber I3 and the temperature of the mixed oiland refrigerant will fall, insufllciently heating the bulb 22 to causeoperation of the thermostat 23 and thus stopping the flow to the annularchamber |3 by the closing of the solenoid valve However, when the heatsupplied from the coil |5 causes the liquid refrigerant to vaporize andconsequently a temperature rise, the bulb 22 will again operate thethermostat 23 and energize the solenoid 24 for opening the valve II. Ifit is so desired, suitable means may be provided for heating the oilreceiver or storage member 2| so as to evaporate out any refrigerantwhich might flow over the weir 20 into this tank, and preventreabsorption of any refrigerant vapor by the oil.

The tank 2| is provided with suitable inlet 25 to permit amake up supplyof oil thereto when necessary. The oil in the storage tank or receiver2| is utilized as a lubricant in the compressors 2 and 3 and it is drawnfrom the storage tank by any suitable type of small Dump, preferably asmall gear pump indicated at 23 which discharges the oil into thecompressor supply line 21; Branch lines 28 lead from the supply line 21to the compressors 2 and 3, and these supply lines have solenoidactuated valves 29 located therein as well as-check valves 30. The checkvalves 30 prevent a back flow of oil from the com pressors into the linewhen the pump 26 is not operating. Float-actuated electric switchstructures 3|, of any approved type which may be purchased upon the openmarket and as shown diagrammatically in the drawing, are connected tothe compressors, and, as is usual in this type of float-operated switch,variations in the level of oil in the compressor operate the switches 3|to make orv break an electric circuit through the motor 32 employed todrive the pump 26.

The quantity of oil in the different compressors will not be uniformlyvaried, that is, one compressor may lose more oil than the other;therefore, to prevent flooding of the compressor and supply to eachcompressor only the amount ofoil the compressor not needing -oil. Thusoil is delivered to the compressors only as and whe needed thereby.

It will be understood that the invention is not to be limited to thespecific construction or arrangement of parts shown, but that they maybe widely modified within the invention defined by the claims.

What is claimed is:

1. In a refrigerating system including a compressor and an evaporatorand a condenser and wherein a refrigerant is evaporated compressed andcondensed to provide refrigeration, an oil separator, means fordelivering mixed refrigerant liquid and oil from the evaporator to saidseparator, and means controlled by the tempera- 4 ture of the mixture ofseparated oil and residual refrigerant in the separator for controllingthe delivery of mixed refrigerant and oil to the separator.

2. In a refrigerating system including a compressor and an evaporatorand a condenser and wherein a refrigerant is evaporated compressed andcondensed to provide refrigeration, an oil separator, means fordelivering mixed refrigerant liquid and oil from the evaporator to saidseparator, means controlled by the temperature ofseparated oil in theseparator for controlling the delivery of mixed refrigerant and oil tothe separator, means for delivering oil from the separator to thecompressor, and means controlled by variances in the level of the oil inthe compressor for controlling the delivery of oil from the separator tothe compressor.

3. In a'refrigerating system including a compressor and an evaporatorand a condenser and wherein a refrigerant is evaporated compressed andcondensed to provide refrigeration, an oil separator, means fordelivering mixed refrigerant liquid and oil from the evaporator to saidseparator, heat exchange means insaid separator for evaporating therefrigerant inthe separatoryto separate the oil therefrom, and meanscontrolled by the temperature of separatedoil in theseparator for'controlling the deliveryof 'xedarefrigerant and oil to the separator, j

4. In a refrigerating system inclu ga comevaporating the refrigerant inthe separator to separate the oil therefrom, means controlled by thetemperature of separated oil in the separator for controlling thedelivery of mixed refrigerant and oil to the separator, and means fordelivering gaseous refrigerant to said heat exchange means from a pointin the system where the temperature of the evaporated gas is sufficientthat the hot gaseous refrigerant circulating through the heat exchangemeans will provide heat for evaporation of the refrigerant; in therefrigerant and gas mixture delivered to the separator.

5. In a refrigerating system including a compressor and an evaporatorand a condenser and wherein a refrigerant is evaporated compressed andcondensed to provide refrigeration, an oil separator, mean fordelivering mixed refrigerant liquid and oil from the evaporator to saidseparator, heat exchange means in said separator for evaporating therefrigerant in the separator to separate the oil therefrom, means fordelivering gaseous refrigerant to said heat exchange mean from a pointin the system where the temperature of the evaporated gas is sufficientto provide heat for evaporation of the refrigerant in the mixture ofrefrigerant and oil delivered to the separator, means controlled by thetemperature of separated oil in the separator for controlling thedelivery of mixed refrigerant and oil to the separator, means fordelivering oil from the separator to the compressor, and means con- Itrolled by variances in the level of the oil in the compressor forcontrolling the delivery of oil from the separator to the compressor.

6. In a refrigerating system including a compressor and an evaporatorand a condenser and wherein a refrigerant is evaporated compressed andcondensed to provide refrigeration, an oil separator, means fordelivering mixed refrigerant liquid and oil from the evaporator to saidseparator, heat exchange means in said separator for separator, an oilstorage receptacle for receiving oilfrom said separator, means fordelivering oil from the storage receptacle to the compressor,

and means controlled by variances in the level of the quantity of oil inthe compressor for controlling the delivery of oil from said receptacleto the compressor.

7. In a refrigerating system including a plurality of compressors; anevaporator and a condenser and wherein a refrigerant i evaporated,compressed and condensed to provide refrigerant; an oil separator;.means for delivering mixed liquid refrigerant and 011 from theevaporator to said oil separator; means for delivering separated out oilfrom the separator to said compressors; means controlled by the level ofoil in each compressor for independently controlling the delivery of oilfrom the separator to each compressor; and means controlled by thetemperature of separated oil in the separator for controlling thedelivery of mixed refrigerant and oil to the separator. I

JOSEPH R. ZWICKL.

REFERENCES CITED Number Date 2,246,244 Consley June 17, 1941

